[ILUG] hashing algorithm

[Smelly Pooh]

In reply to Caolan McNamara's flatulent wordings, 
> At 08:59 05.09.00 +0100, Smelly Pooh wrote:
> >In reply to Caolan McNamara's flatulent wordings,
> > > >How do you go about finding out which one(s) your libc uses/supports?
> > > >Does RedHat6.2 support SHA?
> > >
> > > Are you telling me that there is some sort of standardish c library 
> > hashing
> > > api call ?
> > >
> >The only Linux libc standard I'm afraid is DES crypt, it is quite annoying
> >that a lot of apps re-invent the wheel for crypto functions, however quite a
> >few also use openSSL (www.openssl.org)
> 
> We talking at cross purposes here, just to be clear on everything, SHA1 
> (Secure Hash Algorithm) is a hashing algorithm. They are not intended to 
> encrypt something, just to generate a fixed len chunk of data that uniquely 
> identifys it. Theres no way back from their hash, theres often a use for 
> them in encryption software but something like crypt is not a hashing 
> algorithm and neither is technology like SSL.

I'm afraid openSSL's name is a bit misleading, yes it's best known for SSL
(obviously) but it's also a crypto library (hence a man crypto separate from
the man ssl) and to confuse things even more, hash algorithms are listed
by themselves in their crypto man page.  To clarify, openSSL doesn't only do
SSL, programs like SSH and openPGP uses its crypto functions.  Taken from
their crypto man page, hash algorithms they provide are

AUTHENTICATION CODES, HASH FUNCTIONS

hmac(3), md2(3), md4(3), md5(3), mdc2(3), ripemd(3), sha(3)